An architect shares his plan and process for building a northern Vermont house that produces as much energy as it consumes.

Providing Power

The decision between wind and PV was driven partly by the presence of wind, partly by the cost of PV panels, which has since come down, and partly by rebates available at the time. At $27,000, the cost of a 10kW Bergey turbine, installed, was about half the cost of the 7kW PV system that would have been needed to produce comparable electricity. At that time, the tax credit for alternative energy was capped at $1,500. If I were doing it now, I might choose PV, because it’s gotten much cheaper, plus it’s a simpler setup with less maintenance expense. The turbine will need to be taken down every five years for lubrication.

Wind is also politically tricky — some people love the sight of windmills and some hate them. We were fortunate that our neighbors were actually pleased at the prospect of seeing a windmill. Noise is another issue: The spinning blades definitely produce sound, but when the wind is already blowing, the windmill tends to become part of the background noise.

In looking at wind power, you need a good idea of average wind speed at the site. As the speed increases, power production increases exponentially. At an average wind speed of 12 mph, our Bergey turbine is far superior in output to PV. Wind monitoring would have been very expensive, so I studied wind maps, spoke to the neighbors, and looked for any other signs I could see, such as flagging of trees. I ultimately concluded that it would be cheaper to buy the system and sell the used equipment if it didn’t work out than to spend money on an assessment tower and monitoring equipment. As it turned out, we have an average speed of around 10 mph, less than we originally thought but still enough to offset our energy use.